High temperature lubricant compositions

ABSTRACT

A lubricant composition useful for high temperature applications is provided comprising at least one polyol polyester derived from the reaction product of a neopentyl polyol with 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-octanoic acid. The lubricants have low evaporation loss, high resistance to oxidation, and provide reduced deposits when utilized alone or in combination with other materials.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Application No. 60/763,297, filed Jan. 30, 2006.

BACKGROUND OF THE INVENTION

Lubricants that can maintain their structure under extremes of temperature are useful and essential in many commercial, domestic, and industrial applications. Such applications include, but are not limited to, fiberglass production, wood laminating, wood pressing, paint curing, textile production, and food baking. Lubricants can also be used in aerospace applications in which fluids are exposed to temperatures typically exceeding 200° C. Such high temperature lubrication fluids must also provide sufficient lubrication of metal surfaces to prevent wear, reduce friction, reduce energy consumption, and more importantly, prevent failure of mechanical systems.

Lubricants that are used at high temperatures must also be resistant to thermal and/or oxidative breakdown and polymerization. Thermal and/or oxidative breakdown leads to the scission of lubricant molecules, which in turn, leads to the formation of lower molecular weight compounds that can be volatilized, depending upon the operational conditions of a mechanical system. This process normally results in an increased lubricant viscosity. Where the lubricant is exposed to the atmosphere, and especially in thin films, an increase in lubricant viscosity reduces the mobility of the lubricant liquid, accelerates oxidation, and leads to the formation of deposits. Such breakdown may also result in loss of lubricant fluid and/or the production of excessive vapors and/or smoke, or ineffective lubrication. This, in turn, can lead to mechanical breakdown, higher energy consumption, reduced cleanliness, poorer product quality, and higher occupational exposure to volatile organic compounds. Polymerization can lead to formation of deposits of semi-solid gums and hard varnishes that can build up on metal surfaces and in work environments. This, in turn, may lead to poorer lubrication, higher energy consumption, and potential production stoppages due to the need to remove deposits from the metal surfaces.

Liquid lubricant compositions typically have a base oil to which other additives are provided. The additives impart specific properties to the overall lubricant mixture. One class of such additives is metal protecting additives. These exhibit beneficial properties such as resistance to wear, protection from damage at extreme pressure, and resistance to corrosion. Such additives are also useful for protecting metal surfaces. One drawback of metal protecting additives, however, is that they can reduce stability of the base oils once added.

To alleviate such loss of stability, lubricant protecting additives can be provided to the base oils. Lubricant protecting additives are helpful for maintaining a lubricant's structure under operational conditions. The most important lubricant protecting additives are antioxidants. Antioxidants protect a base oil in a lubricant composition and/or other additives therein from attack by atmospheric oxygen, a harmful process also known as oxidation, which produces unwanted free radicals and leads to instability. Antioxidants help to stabilize base oils by helping to prevent oxidation. The effectiveness of antioxidants is strongly influenced by the level of stability of the base oil or oils in the composition. Greater stability of the base oil helps to reduce potentially adverse effects of oxidation.

A few types of compounds are routinely used as liquid base oils in the field of high temperature lubricants, include perfluoropolyalkyl ethers which are highly resistant to oxidation due to the complete absence of extractable hydrogen atoms. Polyphenylethers and alkyldiphenyl ethers are also inherently very stable. However, their lubrication properties are poorer than other classes of base oils, and they tend to be either incompatible and/or not positively responsive to metal and/or lubricant protecting additives. Additionally, due to the sophisticated synthesis techniques and manufacturing processes required to produce these materials, they are only produced in small quantities unsuitable for large-scale industrial use.

Another class of compounds commonly used as liquid base oils in the lubrication field is synthetic esters. Synthetic esters are derived from the reaction of carboxylic acids and alcohols. Carboxylic acids and alcohols can be synthesized to very high purity, and thus, synthetic esters can be designed with very defined structures that can be targeted to provide the specific properties sought in a particular application. Synthetic esters are generally both compatible with, and respond favorably to common metal and lubricant protecting additives.

Esters of certain carboxylic acids and alcohols are known to possess enhanced resistance to thermal and/or oxidative breakdown. Two general classes of commonly used synthetic esters with one or more of these properties are aromatic esters and neopolyol esters. Aromatic esters are formed as a reaction product of aromatic polycarboxylic acids, such as trimellitic acid and pyromellitic acid, and linear and/or branched monofunctional alcohols. Such alcohols typically have a carbon chain length of about 8 to about 13 carbon atoms. Although aromatic esters are prone to oxidation due to the aromatic portion of the molecule, they can be useful due to their relatively high molecular weight and structural purity that contributes to a lower volatility. U.S. Pat. No. 6,465,400 discloses a lubricant composition prepared by mixing aromatic esters with an additional base oil and antioxidants.

Neopolyol esters are formed from the reaction of neopentyl polyols, such as neopentyl glycol, trimethylolpropane, pentaerythritol, and dipentaerythritol with linear and/or branched carboxylic acids that are typically about two to about ten carbon atoms in chain length. Neopolyol esters as a class are generally more resistant to oxidation than aromatic esters. They are particularly useful due to their higher thermal and oxidative stability which stems from the absence of hydrogens attached to carbons that are β to the ester linkage, which can lead to a low energy oxidation pathway. The carboxylic acids used to form such esters typically are linear and/or branched chain acids having from about five to about ten carbon atoms. U.S. Pat. No. 4,826,633 discloses esters formed by reacting trimethylolpropane and monopentaerythritol with a mixture of linear and branched carboxylic acids having from 5 to 10 carbon atoms. U.S. Pat. No. 6,436,881 discloses a high temperature lubricant formulation formed by reacting mainly dipentaerythritol with a mixture of linear and branched carboxylic acids having from 5 to 12 carbon atoms, that also includes a viscosity index improver. U.S. Pat. No. 6,884,861 discloses a high temperature lubricant composition including esters formed from the reaction of certain polyols with mixtures of carboxylic acids having a five to ten carbon chain length and/or aromatic acids.

Neopentyl polyol polyesters that are formed from certain relatively short chain linear or branched carboxylic acids of about 5 to about 10 carbons are particularly resistant to thermal and/or oxidative breakdown and/or polymerization relative to neopentyl polyol polyesters derived from longer chain carboxylic acids of about 12 carbons and longer. Examples of shorter chain carboxylic acids employed for forming neopentyl polyol polyester for use as base oils in lubricant compositions are pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, 2-ethylhexanoic acid, nonanoic acid, 3,5,5-trimethylhexanoic acid (isononanoic acid) and decanoic acid. The shorter chain carboxylic acids are preferred due to the shielding effect provided by the ester linkage that makes the hydrogen atoms on the carboxylic acid portion more resistant to abstraction and resultant oxidative attack. Longer chain carboxylic acids generally possess hydrogen atoms further away from the ester linkage that do not benefit from increased stability provided from the shielding effect of the ester linkage.

Although using shorter chain carboxylic acids improves resistance to oxidation, the resulting molecular weight of the ester is typically limited, which can lead to higher volatility. Isononanoic acid is particularly resistant to oxidation due to the reduced presence of secondary hydrogen atoms and the steric crowding about the lone tertiary hydrogen atom. However, due to its highly branched nature, the resulting esters generally have higher volatility. Higher volatility of the base ester, and resulting oxidative scission products can lead to oil thickening that accelerates the formation of deposits, especially in thin films.

Therefore, there is a need in the art for an improved ester that combines the desirable thermal and oxidative stability typically provided by the reaction of neopentyl polyols with shorter chain carboxylic acids; the low volatility and/or low volatility of oxidation scission products, which, in the past, have been associated with the use of longer chain carboxylic acids to form the neopentyl polyol ester; and the low volatility that arises from the use of aromatic polycarboxylic acids to form the aromatic ester.

BRIEF SUMMARY OF THE INVENTION

The present invention includes a lubricant composition that has at least one polyol polyester. The polyol polyester comprises the reaction product of at least one neopentyl polyol and 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-octanoic acid or a reaction product, mixture, or copolymer thereof, or a further reaction product, further mixture, or further copolymer of the reaction product.

In one embodiment, the reaction product is a base oil in a lubricant composition. In a further embodiment, the lubricant composition including the reaction product as a base oil comprises at least one additional base oil. In yet a further embodiment, the lubricant composition including the reaction product as a base oil and comprising at least one additional base oil further comprises a lubricant protecting additive and/or a metal protecting additive.

One embodiment of the present invention includes providing a lubricant composition that has at least one polyol polyester. The polyol polyester is the reaction product of a neopentyl polyol and 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-octanoic acid or reaction products, mixtures, and copolymers. The reaction product is a base oil in the composition, and the composition also has at least one additional base oil.

The invention also includes a lubricant composition that has at least one polyol polyester. The polyol polyester is the reaction product of a neopentyl polyol and 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-octanoic acid or reaction products, mixtures, and copolymers thereof. The reaction product is a base oil in the composition, and the composition further also has at least one additional base oil, at least one metal protecting additive, and/or at least one lubricant protecting additive.

Also included herein is a method of lubricating a metal surface. The method comprises applying a lubricant composition to a metal surface, wherein the lubricant composition comprises a) a reaction product of at least one neopentyl polyol and 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-octanoic acid or a reaction product, mixture, or copolymer thereof wherein the reaction product is a base oil in the composition, b) at least one additional base oil, c) from about 0.5 to about 15 percent by weight of at least one lubricant protecting additive, and d) from about 0.1 to about 10 percent by weight of at least one metal protecting additive.

Further, a method of making a lubricant composition, is included. The method comprises reacting a) at least one neopentyl polyol and b) 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-octanoic acid or a reaction product, mixture, or copolymer thereof, wherein the reaction product is a base oil in the composition.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates generally to lubricant compositions useful for high temperature applications comprising polyol polyesters derived from 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-octanoic acid and reaction products, mixtures, and copolymers thereof. It should be understood based on this disclosure hereinafter that when referring to “5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-octanoic acid” herein included within the scope thereof are reaction products, mixtures and copolymers thereof.

The present invention provides lubricant compositions that exhibit high resistance to thermal and/or oxidative breakdown and/or polymerization, low volatility, and a low deposit formation tendency. Examples of such lubricant compositions include, but are not limited to, those that include the reaction product of at least one neopentyl polyol and 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-octanoic acid as well as further reaction products, mixtures, and copolymers of that reaction product. In addition, it includes lubrication compositions that include an additive that is the reaction product of at least one neopentyl polyol and 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-octanoic acid as well as mixtures, reaction products and copolymers of that reaction product. Further, base oils are provided which are a mixture of the reaction product of at least one neopentyl polyol and 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-octanoic acid, and reaction products, mixtures, and copolymers of that reaction product's derivatives as noted above, and at least one additional base oil such as other base compositions including various mixtures of the reaction product noted above with at least one additional base oil, at least one metal protecting additive and/or at least one lubricant protecting additive.

When the reaction product noted above is used as a base oil to a lubricant composition, it is preferred to be used in amounts of about 0.5 to about 99.5 percent by weight of the composition, more preferably about 1 to about 95 percent by weight or about 5 to about 95 weight percent, and most preferably about 5 to about 50 weight percent, wherein the weight percentages are based on the total weight percent of the lubricant composition. If additional base oils are provided, they may be used in similar quantities, and preferably, when the base oil including the reaction product is about 5 to about 50 weight percent of the composition, the additional base oil(s) make up about 50 to about 90 percent of the lubricant composition. The ratio of the base oil having the reaction product to the additional base oils is preferably from about 99:1 to about 1:99, more preferably 25:75 to about 75:25, still more preferably about 30:70 to about 70:30, and most preferably about 50:50.

The mechanism of oxidation (autoxidation) is commonly described by the “hydroperoxide theory.” The hydroperoxide theory in its most basic form can be summarized in the series of reaction steps depicted below:

Step Reaction formation of free radical RH → R• + •H formation of peroxy radical R• + O₂ → ROO• formation of hydroperoxide ROO• + RH → ROOH + R• Propagation ROOH → RO• + •OH RO• + RH → ROH + R• HO• + RH → HOH + R•

Depending upon the nature of the substrate chemical, the specific course of reaction, the kinetics of the reaction, the rate dependency upon temperature, or the presence of metal catalysts, enzymes, or ultraviolet radiation that can impact the reaction kinetics, a virtually infinite variety of by-products may be observed. Based upon this theory, the primary factor in the prediction of oxidation stability when inspecting a molecular structure is the identification of hydrogen atoms that may be easily abstracted to form free radicals. Since free radicals are formed chemically by homolytic cleavage of carbon-hydrogen bonds, a first estimate can be obtained simply by looking at bond dissociation energies.

Alkyl substituents contribute electron density and stabilize free radicals. Tertiary hydrogen atoms are most easily abstracted, followed by secondary, then primary. The exact position of alkyl groups within a carbon chain can also have the effect of either stabilizing or de-stabilizing the molecule by steric crowding, or by eliminating the possibility of non-oxidative degradation reactions such as dehydration that can give rise to by-products that are easily oxidized.

The structure of 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-octanoic acid (available commercially as Fine Oxocol™ Isostearic Acid, from Nissan America Chemical Corporation, Houston, Tex., USA) is depicted below:

As can be seen from the structure, this carboxylic acid possesses eighteen (18) carbon atoms, eight (8) sterically crowded secondary hydrogen atoms, two (2) highly sterically crowded tertiary hydrogen atoms, and one (1) tertiary hydrogen atom adjacent to the carboxylic acid. All other hydrogens within this molecule are primary. The hydrogen atoms located in close proximity to the ester linkages are more difficult to extract. Neopentyl polyols possess only primary hydrogen atoms.

One embodiment of the present invention is a lubricant composition, including as a base oil and/or a liquid, a polyol polyester formed as the reaction product of, preferably from the esterification of, at least one neopentyl polyol and 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-octanoic acid or its reaction products, mixtures, and copolymers. The composition may also include further reaction products, mixtures or copolymers of the reaction product noted above. The preferred polyol polyester has a viscosity of from about 100 centistokes to about 25,000 centistokes when measured at 40° C. More particularly, the polyol used to make the polyol polyester is a neopentyl polyol. Such neopentyl polyols include, but are not limited to, neopentyl glycol, trimethylolpropane, trimethylolethane, monopentaerythritol, ditrimethylolpropane, dipentaerythritol, tripentaerythritol, and tetrapentaerythritol. Such neopentyl polyols are commercially available, however, it is within the scope of the invention to use both commercially available neopentyl polyols as well as synthesized or modified neopentyl polyols. Preferred polyols are monopentaerythritol and trimethylolpropane or combinations thereof, although minor quantities of dipentaerythritol, tripentaerythritol, and tetrapentaerythritol may be utilized in combination or admixture therewith.

In one embodiment, the invention encompasses a base oil that includes a mixture of a liquid polyol polyester formed from the esterification of at least one polyol and 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-octanoic acid (and its variations as noted above) or any reaction products, mixtures of copolymers of such polyol polyester, and at least one additional base oil. Preferred additional base oils include those known or to be developed in the lubricant arts, such as, for example, synthetic esters, polyesters, complex polyol polyester polymers, poly α-olefins, polymer esters, such as, for example, Ketjenlube®, commercially available from Akzo Nobel, alkylated naphthalenes, polyalkylene glycols, silicones, phosphate esters, alkylated aromatics, silahydrocarbons, phosphazenes, polyphosphazenes, dialkylcarbonates, cycloaliphatics, polybutenes, alkyldiphenyl ethers, polyphenyl ethers, mineral oils, hydrocarbon oils, triglyceride oils, vegetable oils, fatty acids having a primary carbon chain length of about 5 to about 54 carbon atoms, and copolymers, mixtures, derivatives, and combinations of these materials.

Synthetic esters may include, but are not limited to, neopentyl polyol esters, complex polyol polyesters, and aromatic esters. Preferred synthetic esters are neopentyl polyol polyesters and/or neopentyl polyol polyester polymers. Neopentyl polyol polyesters referred to herein are the reaction products of neopentyl polyols with at least one monofunctional carboxylic acid, and having multiple ester linkages in the molecule. Such materials are typically not polymeric in character. Neopentyl polyol polyester polymers are the reaction products of neopentyl polyols and at least one polyfunctional carboxylic acid and at least one monofunctional carboxylic acid and/or a monofunctional alcohol as an end capper. Such materials are polymeric in character and are also known as complex esters or complex polyol esters.

Preferred neopentyl polyol polyesters include the reaction products of neopentyl polyols with linear and/or branched carboxylic acids of chain length of about 5 to about 12 carbon atoms. Preferred neopentyl polyol polyester polymers include the reaction products of at least one neopentyl polyol, at least one polycarboxylic acid, and at least one linear and/or branched monocarboxylic acid and/or alcohol of chain length of about 5 to about 20 carbon atoms.

Such lubricant compositions preferably include such as, for example, metal protecting additives t-butylphenyl phosphates, amines; branched alkyls of from 11 to 14 carbon atoms, monohexyl and dihexyl phosphates, isopropylphenylphosphates, tricresyl phosphates, trixylyl phosphates, di(n-octyl)phosphite, alkylated triphenylphosphorothionate, triphenylthiophosphate, benzotriazole, tolyltriazole, and mixtures, derivatives, and combinations thereof.

About 0.1 to about 10 percent by weight of the total composition of at least one metal protecting additive is preferably used when provided such an optional additive to a preferred lubricant composition. More particularly, up to about 5 percent by weight of the lubricant composition of metal protecting additive is provided to the lubricant composition.

Lubricant protecting additives include any such additive known or to be developed in the lubricant art, but are not limited to, benzenamine, N-phenyl-, reaction products with 2,4,4-trimethylpentene; N-phenyl-1,1,3,3-tetramethylbutylnaphthalen-1-amine; butylated hydroxytoluene; alkylated diphenylamine; nonylated diphenylamine; styrenated diphenylamine; hindered alkylphenols; benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy-, thiodi-2,1-ethanediyl ester; benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy-, 2,2-bis[[3-[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]-1-oxopropoxy]methyl]-1,3-propanediyl ester;

thiphenolic derivatives, and mixtures, derivatives, and combinations of these materials. About 0.5 to about 15 percent by weight of at least one lubricant protecting additive is preferably added to the lubricant composition. More particularly, up to about 5 percent by weight of an optional lubricant protecting additive is provided to the lubricant composition.

The invention will now be explained with respect to the following, non-limiting Examples. In the following Examples, kinematic viscosity was tested using ASTM International, West Conshohocken, Pa., USA, (standard test method ASTM-D-445-97 (1997). Total acid number (TAN) was determined using ASTM D-972. Hydroxyl value (OH) was determined using ASTM D-1957. Viscosity index (VI) was determined using ASTM D-2270. Flash point was determined using ASTM D-92, and pour point was determined using ASTM D-97.

Evaporation loss, deposit formation tendency, and residual oil fluidity were assessed by the following procedure. The lubricant base oil was blended with 1.5 wt. % each of benzenamine, N-phenyl-, reaction products with 2,4,4-trimethylpentene (Vanlube® 81, commercially available from RT Vanderbilt Corporation, Norwalk, Conn., USA) and N-phenyl-1,1,3,3-tetramethylbutylnaphthalen-1-amine (Irganox® LO-6, commercially available for Ciba Specialty Chemicals Corporation, Tarrytown, N.Y., USA). Two (2) grams of lubricant liquid were placed in an aluminum weighing dish, and then placed in a muffle furnace. The test condition of 288° C. was held for 5½ hours. Evaporation loss, deposit formation tendency, and flow properties of the lubricant after this procedure were measured by weight and by visual observation, respectively.

EXAMPLE 1

The lubricant composition trimethylolpropane tri-5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-octanoate (TMPTTBO) was prepared by combining the following materials of Table 1 in a batch reactor fitted with a mechanical stirrer, inert gas sparge, vapor column, condenser, and distillate receiver. Pressure in the reactor was controlled by a vacuum pump that was attached to the reactor.

TABLE 1 Parts Per 100 Moles Per 100 Component Parts Parts Trimethylolpropane 13.6 0.101 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)- 86.4 0.304 octanoic acid

About 0.10 parts per 100 parts tetrabutyltitanate was added to the reaction mixture, and the mixture was heated to from about 180° C. to about 250° C. Pressure was slowly reduced until sufficient conversion was obtained. The crude ester was further purified by steam distillation and filtration. The result was a yellow viscous liquid possessing the following properties shown in Table 2:

TABLE 2 Property, Units Test Method Result Total Acid Number, mg KOH/g ASTM D-972 0.38 Hydroxyl Number, mg KOH/g ASTM D-1957 4.7 Kinematic Viscosity @ 40° C., cSt ASTM D-445 2,411 Kinematic Viscosity @ 100° C., cSt ASTM D-445 44.6 Viscosity Index ASTM D-2270 −22 Flash Point (C.O.C), ° C. ASTM D-92 280 Evaporation Loss, % 48.8 Deposits After Heating, Visual Minimal Fluidity After Heating, Visual Fluid

EXAMPLE 2

The lubricant composition Trimethylolpropane/Pentaerythritol 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-octanoate (TMPPETTBO) was prepared by combining the following materials in Table 3 in a batch reactor fitted with a mechanical stirrer, inert gas sparge, vapor column, condenser, and distillate receiver. Pressure in the reactor was controlled by a vacuum pump that was attached to the reactor.

TABLE 3 Parts Per 100 Moles Per Component Parts 100 Parts Trimethylolpropane 9.5 0.071 Pentaerythritol 3.2 0.024 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)- 87.3 0.307 octanoic acid

About 0.10 parts per 100 parts tetrabutyltitanate was added to the reaction mixture, and the mixture was heated to from about 180° C. to about 250° C. The pressure was slowly reduced until sufficient conversion was obtained. The crude ester was further purified by steam distillation and filtration. The result was a yellow viscous liquid possessing the following properties listed in Table 4:

TABLE 4 Property, Units Test Method Result Total Acid Number, mg KOH/g ASTM D-972 0.31 Hydroxyl Number, mg KOH/g ASTM D-1957 0.42 Kinematic Viscosity @ 40° C., cSt ASTM D-445 3,157 Kinematic Viscosity @ 100° C., cSt ASTM D-445 53.8 Viscosity Index ASTM D-2270 −8 Flash Point (C.O.C), ° C. ASTM D-92 286 Evaporation Loss, % 44.1 Deposits After Heating, Visual Minimal Fluidity After Heating, Visual Fluid

EXAMPLE 3

A lubricant base oil was prepared by combining the following ingredients of Table 5:

TABLE 5 Component Parts Per 100 Parts TMPTTBO 50 Synthetic Ester 50

The result was a yellow viscous liquid possessing the following properties shown in Table 6:

TABLE 6 Property, Units Test Method Result Total Acid Number, mg KOH/g ASTM D-972 0.17 Hydroxyl Number, mg KOH/g ASTM D-1957 4.5 Kinematic Viscosity @ 40° C., cSt ASTM D-445 401.4 Kinematic Viscosity @ 100° C., cSt ASTM D-445 20.0 Viscosity Index ASTM D-2270 35 Flash Point (C.O.C), ° C. ASTM D-92 270 Pour Point, ° C. ASTM D-97 −15 Evaporation Loss, % 58.7 Deposits After Heating, Visual Minimal Fluidity After Heating, Visual Fluid

EXAMPLE 4

A lubricant base oil was prepared by combining the following ingredients of Table 7:

TABLE 7 Component Parts Per 100 Parts TMPTTBO 57 Synthetic Ester 43

The result was a yellow viscous liquid possessing the following properties of Table 8:

TABLE 8 Property, Units Test Method Result Total Acid Number, mg KOH/g ASTM D-972 0.26 Hydroxyl Number, mg KOH/g ASTM D-1957 4.57 Kinematic Viscosity @ 40° C., cSt ASTM D-445 363.0 Kinematic Viscosity @ 100° C., cSt ASTM D-445 20.8 Viscosity Index ASTM D-2270 58 Flash Point (C.O.C), ° C. ASTM D-92 290 Pour Point, ° C. ASTM D-97 −21 Evaporation Loss, % 40.8 Deposits After Heating, Visual Minimal Fluidity After Heating, Visual Fluid

EXAMPLE 5

A lubricant base oil was prepared by combining the following ingredients of Table 9:

TABLE 9 Component Parts Per 100 Parts TMPTTBO 15 Synthetic Ester 85

The result was a yellow viscous liquid possessing the following properties of Table 10:

TABLE 10 Property, Units Test Method Result Total Acid Number, mg KOH/g ASTM D-972 0.06 Hydroxyl Number, mg KOH/g ASTM D-1957 1.9 Kinematic Viscosity @ 40° C., cSt ASTM D-445 489 Kinematic Viscosity @ 100° C., cSt ASTM D-445 27.0 Viscosity Index ASTM D-2270 27 Flash Point (C.O.C), ° C. ASTM D-92 306 Pour Point, ° C. ASTM D-97 −18 Evaporation Loss, % 71.5 Deposits After Heating, Visual Minimal Fluidity After Heating, Visual Fluid

EXAMPLE 6

To illustrate the improvement that can be made by use of TMPTTBO as an additive, the following mixtures of Table 11 were prepared by blending the fluids at about 70 to about 90° C. with mechanical agitation until a clear uniform solution was obtained.

TABLE 11 Mixture B Mixture A Parts Per 100 Component Parts Per 100 Parts Parts TMPTTBO 29.1 — Poly α-olefin 40 67.9 58.2 Poly α-olefin 100 — 38.8 Vanlube ® 81 1.5 1.5 Irganox ® LO-6 1.5 1.5

The solutions were then tested for thin film heat stability. Two grams of lubricant were placed in an aluminum weighing dish, placed in a muffle furnace, and held for a test duration of 5½ hours at 288° C. Evaporation loss, deposits, and flow properties of the lubricant after the test were measured by weight and by visual observation, respectively.

The results are provided below in Table 12:

TABLE 12 Property, Units Mixture A Mixture B Evaporation Loss, % 21.7 31.3 Deposits After Heating, Visual Minimal Significant Fluidity After Heating, Visual Fluid Non Fluid Tar

The test results indicated significant reduction in volatility, reduced deposits, and improved fluidity of aged oil when polyalphaolefin was replaced with TMPTTBO.

It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims. 

1. A lubricant composition comprising at least one polyol polyester, wherein the polyol polyester comprises a reaction product of: a) at least one neopentyl polyol, and b) 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-octanoic acid or a reaction product, mixture, or copolymer thereof, or a further reaction product, further mixture or further copolymer of the reaction product.
 2. The lubricant composition of claim 1, wherein the neopentyl polyol is selected from the group consisting of neopentyl glycol, trimethylolpropane, trimethylolethane, monopentaerythritol, ditrimethylolpropane, dipentaerythritol, tripentaerythritol, and tetrapentaerythritol.
 3. The lubricant composition of claim 1, wherein the reaction product is a base oil in the composition and the composition further comprises at least one additional base oil.
 4. The lubricant composition of claim 3, wherein the base oil is from about 1 to about 95 percent by weight of the lubricant composition and the additional base oil is about 1 to 95 percent of the lubricant composition.
 5. The lubricant composition of claim 3, wherein the base oil is from about 5 to about 50 percent by weight of the lubricant composition and the additional base oil is about 50 to 90 percent of the lubricant composition.
 6. The lubricant composition of claim 3, wherein the additional base oil is selected from the group consisting of synthetic esters, polyesters, complex polyol polyester polymers, poly α-olefins, polymer esters, alkylated naphthalenes, polyalkylene glycols, silicones, phosphate esters, alkylated aromatics, silahydrocarbons, phosphazenes, polyphosphazenes, dialkylcarbonates, cycloaliphatics, polybutenes, alkyldiphenyl ethers, polyphenyl ethers, mineral oils, hydrocarbon oils, triglyceride oils, vegetable oils, fatty acids having a primary carbon chain length of about 5 to about 54 carbon atoms, and copolymers, mixtures, derivatives, and combinations thereof.
 7. The lubricant composition of claim 4, wherein the additional base oil is a synthetic ester selected from the group consisting of neopentyl polyol esters, complex polyol polyesters, alkylated naphthalenes and aromatic esters.
 8. The lubricant composition of claim 4, wherein the additional base oil is a poly α-olefin.
 9. The lubricant composition of claim 1, further comprising from about 0.5 to about 15 percent by weight based on a weight of the lubricant composition of at least one lubricant protecting additive.
 10. The lubricant composition of claim 7, wherein the lubricant protecting additive is present in the amount of up to about 5 percent by weight based on the weight of the lubricant composition.
 11. The lubricant composition of claim 7, wherein the lubricant protecting additive is selected from the group consisting of benzenamine, N-phenyl-, reaction products with 2,4,4-trimethylpentene; N-phenyl-1,1,3,3-tetramethylbutylnaphthalen-1-amine; butylated hydroxytoluene; alkylated diphenylamine; nonylated diphenylamine; styrenated diphenylamine; hindered alkylphenols; benzenepropanoic acid; 3,5-bis(1,1-dimethylethyl)-4-hydroxy-, thiodi-2,1-ethanediyl ester; benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy-, 2,2-bis[[3-[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]-1-oxopropoxy]methyl]-1,3-propanediyl ester; thiphenolic derivatives; and mixtures; derivatives; and combinations thereof.
 12. The lubricant composition of claim 1, further comprising from about 0.1 to about 10 percent by weight of at least one metal protecting additive based on a weight of the lubricant composition.
 13. The lubricant composition of claim 10, wherein the metal protecting additive is present in the amount of up to about 5 percent by weight based on the weight of the lubricant composition.
 14. The lubricant composition of claim 10, wherein the metal protecting additive is selected from the group consisting of t-butylphenyl phosphates, amines; branched alkyls of from about 11 to about 14 carbon atoms, monohexyl and dihexyl phosphates, isopropylphenylphosphates; tricresyl phosphates; trixylyl phosphates; di(n-octyl)phosphate; alkylated triphenylphosphorothionate; triphenylthiophosphate; benzotriazole; tolyltriazole; and mixtures; derivatives; and combinations thereof.
 15. A method of lubricating a metal surface, comprising: applying a lubricant composition to a metal surface, wherein the lubricant composition comprises: a) a reaction product of at least one neopentyl polyol and 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-octanoic acid or a reaction product, mixture, or copolymer thereof wherein the reaction product is a base oil in the composition, b) from about 0.5 to about 15 percent by weight of at least one lubricant protecting additive, and c) from about 0.1 to about 10 percent by weight of at least one metal protecting additive.
 16. The method of lubricating, according to claim 15, wherein the lubricant composition further comprises at least one additional base oil.
 17. The method of lubricating, according to claim 16, wherein the lubricant composition comprises about 5 to about 50 percent of the reaction product (a) and about 50 to about 90 percent of the at least one additional base oil.
 18. A method of making a lubricant composition, comprising reacting a) at least one neopentyl polyol and b) 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-octanoic acid or a reaction product, mixture, or copolymer thereof, wherein the reaction product is a base oil in the composition.
 19. The method of claim 18, further comprising providing at least one additional base oil.
 20. The method of claim 19, wherein the base oil is from about 5 to about 50 percent by weight of the lubricant composition and the additional base oil is about 50 to 90 percent of the lubricant composition.
 21. The method of claim 14, further comprising providing from about 0.5 to about 15 percent by weight based on a weight of the lubricant composition of at least one lubricant protecting additive.
 22. The method of claim 14, further comprising providing from about 0.1 to about 10 percent by weight based on a weight of the lubricant composition of at least one metal protecting additive. 